Electric furnace



J. c. WOODSON ELECTRIC FURNACE Filed Feb. 6. 1929 m bmk NNNT Aug. 2, 1932.

INVENTOR James O Woodson.

TTORN EY Patented Aug. 2, 1932 UNITED STATES JAMES C. 'WO ODSON, OF MANSFIELD, OHIO, ASSIGNOR, T WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA ELECTRIC FURNACE A Application filed February 6, 1929. Serial No. 337,797.

My invention relates to furnaces and more particularly to recuperative furnaces.

An object of my invention is to provide a relatively simple and compact furnace struc- [BJture for a recuperative furnace that shall heating means are so located that no heat will be directly radiated therefrom through the open ends of straight portions of the chamber.

In practicing my invention, I provide a 29 pair of straight and substantially parallelextending chamber portions located in sideby-side relation, each end of each chamber being open, together with a heating chamber of substantially U-shape, directly communieating with one end of the open straight chambers. Electric heating elements are located on the walls and on the floor of the chamber of U-shape and extend over substantially the arcuate portion only, the radius of curvature of the arcuate portion of the chamber being relatively much greater than half the distance between the center lines of the straight and parallel extending chambers.

Referring to the single sheet of drawings,

Figure 1 is a view, in horizontal section, through a furnace embodying my invention,

Fig. 2 is a View, in vertical longitudinal secsion, taken on the line IIII of Fig. 1, an

Fig. 21 is a View, in vertical lateral section, taken on the line III-III of Fig. 1.

The furnace structure designated generally by numeral 11 comprises two outer vertical walls 12 and 18, a floor 14, together with a plurality of columns 16 located between the two walls 12 and 13 to define two straight recuperative chambers 17 and 18. The chambers 17 and. 18 are in lateral communication with each other by reason of the spaces be tween the columns 16.

The walls 12, 13 and 1 and the columns 16 may be made of any suitable refractory material usually employed in the construction of preheating or recuperative furnaces of this general kind, and as the specific details of construction of the furnace walls constitute no part of my invention, 1 have elected to show them generally only.

A plurality of structural metal members 19, here shown as I-beams, are provided in spaced location along the outside of the walls 12 and 13, which vertically extending members may be bridged and connected at their upper ends by I-beam members 21. v

a A roof structure 22 is provided which may also be made of refractory material of any suitable or desired character, usually employed in furnaces of'this kind. This roof is provided with two longitudinally extending slots or openings 23 and 24 which extend over the respective chambers 17 and 18 for their entire lengths.

A second portion of the furnace, structure may be described as being either of substan: tially U-shape or of arcuate shape and comprises an arcuate outer wall 26 and an inner arcuate wall 27, each being of substantially the same construction as hereinbefore set forth for the walls 12 and 13. The radius of curvature of the chamber 28, located between and defined by the side walls 26 and 27 and a roof portion 29 and the floor 14 is much larger than half the distance between the center lines of the chambers 17 and 18. The ends of the chamber 28 communicate directly with one of the ends of chambers 17 and 18.

I-beams 19 may be provided both on the outside of the outer wall 26 as well as on the inside of the inner wall 27 and cross braces 21 may be employed here also, in order to provide not only a stable furnace structure, but also to provide means for supporting a mate rial-moving means.

As shown generally only in the drawing,

' and more particularly in Fig. 3 of the drawing, I prefer to employ on overhead materialmoving means embodying suitable track means (not shown in detail) supported by the super-structure above the ceiling 22, a flexible chain having material supporting means 31 depending therefromat spaced intervals. Material moving means of this kind are old in the art and as my invention does not reside specifically in the details of construction of this material moving means, I prefer not to show the material moving means in detail and do not desire to be limited to the overhead material moving means as other means, such as a track in the furnace chambers and means for moving cars therealong may be provided.

Heating means are provided in the chamber of arcuate form only, and as shown in Figs. 1 and 2 of the drawing, I prefer to employ electric resistor members 32, suitably supported by and against the side walls of the chamber and, if necessary, additional re-' sistor members 33 located on the floor. These heating resistors are distributed substantially uniformly over the floor and the side walls of arcuate shape and, as shown more particularly in Fig. 1 of the drawing, they extend but a slight distance beyond the arcuate portion of the chamber 28. This is desirable for two reasons, the first reason is that it is possible, by this construction, to obtain substantially uniform distribution of the heating element along the walls and the floor of the heating chamber 28 and the second reason is that there will be no direct radiation of heat from the heating elements and particularly those resistors located against the inner wall 27 through the otherwise open end of the two furnace chambers 17 and 18. There is, therefore, no black body radiation from the resistors or the heated walls of the heating chamber 28 through the open ends of chambers 17 and 18.

Inspection doors 34 are provided, located at suitable points along the furnace structure to permit of inspection of the furnace or of removal of material which may have fallen from the material moving means.

I provide also, means for shutting off the heatlng chamber 28 from the recuperating chambers 17 and 18 and these may be in the form of vertically movable doors 36 and 37 located at the junction of the arcuate chamber 27 and of the recuperating chambers 17 and 18. Any suitable means for moving these doors may be provided and this has been shown schematically only. Means for still further conserving the heat in the furnace structure comprises flap doors 38 and 39, the doors 38 being located at about the midlength of the chambers 17 and 18 and the doors 39 atthe open ends thereof.

If the furnace is to be shut down for a relatively short period of time only, the doors 3% and 37 may be closed by being moved upwardly and the heat in the relatively highly heated chamber 28 will be conserved therein.

remote where enameling Work is beingv done and if r the material to be-enameled comprises relatively large plates, such as may be used in ranges of various kinds. Depending upon the heating of the furnace chamber and possibly accentuated by prevailing winds, a relatively large amount of air flows through such an open-ended furnace structure and therefore not only reduces the thermal efficiency thereof, but also makes it possible that the material will not be uniformly enameled.

A furnace of the kind hereinbefore described and embodying my invention, will have a much smaller, if not almost negligible amount of air flowing through the three chambers, as the arcuate chamber at one end thereof will act to a great extent as a pocketing means for preventing excessive draft or movement of air through the chambers.

It is highly desirable that the radius of curvature of the chamber 28 be made much larger than half the distance between the center lines of the chambers 17 and 18, not only in order to permit of mounting a uniformly distributed heating element on the walls of the chamber 28, but also of insuring that material moved through the heating chamber will not accidently be Caused to engage because of too small radius of curvature of the track. It is obvious also that if the radius of curvature is very small or if a return-bend having a radius equal to half the distance between center lines of-the straight chambers is used, that the material moving means might not operate properly on the very sharp bend.

By locating the preferably electric heating means in the arcuate portion only of the chamber of U-shape, black body-radiation from the open ends of the chambers is effec tively prevented.

Various modifications may be made in the device embodying my invention without departing from. the spirit and scope thereof and I desire that only such limitations shall be placed thereon as are imposed by the prior art or are set forth in the appended claim.

I claim as my invention:

A furnace structure comprising two straight and substantially parallel-extending Lemme chambers located in side-by-side relation, each having open ends, a chamber of substantially U-shape, located at one end of the two chambers and communicating directly there- 5 with, the radius of curvature of the chamber of U-shape bein greater than half the dis tance between t e center lines of the two parallel-extending chambers, and an electric heating element distributed substantially 10 uniforml over the floor and the side walls of the chamber of U-shape and extending over substantially the arcuate length of the chamber of U-shape.

In testimony whereof, I have hereunto sub- 15 scribed my name this 29 day of Janna 1929. JAMES C. WOOD ON. I 

